Left ventricular outflow tract obstruction in transcatheter mitral interventions: percutaneous anterior leaflet modification

Left ventricular outflow tract obstruction (LVOTO) remains one of the most catastrophic complications of transcatheter mitral valve replacement (TMVR) interventions, including TMVR in native valve, valve-in-valve, valve-in-ring, and valve-in-mitral annular calcification procedures. Its incidence varies widely across procedural types (0%-40%), with mortality rates approaching 36%, and represents a leading cause of patient ineligibility, excluding 4%-50% of candidates from TMVR. Accurate pre-procedural risk stratification relies on cardiac computed tomography, which enables annular sizing, virtual valve implantation, neo- and skirt neo-left ventricular outflow tract area quantification, and fluoroscopic projection planning. Key anatomic determinants of LVOTO include anterior mitral leaflet length, aortomitral angle, septal hypertrophy, left ventricular cavity size, and device-related factors. To mitigate LVOTO risk and expand treatment eligibility, in addition to septal modification, anterior mitral leaflet modification techniques have emerged, broadly categorized into electrosurgical laceration approaches-LAMPOON and ELASTA-and balloon-assisted translocation techniques for balloon-expandable valves-BATMAN, CLEVE, DETROIT, and ROBIN. Each strategy addresses distinct anatomic substrates and procedural scenarios, and their complementary profiles support individualized technique selection. This review aims to present an in-depth discussion of LVOTO in TMVR and anterior leaflet modification strategies.